Adhesive compositions containing ionene elastomers

ABSTRACT

Ionene elastomers are prepared by reaction of polymeric diamines and certain dihalide linking agents. These elastomers have utility in coating compositions, adhesive compositions, and in the fabrication of elastomeric articles. Certain novel dihalide linking agents are also claimed.

This is a division of application Ser. No. 801,281, filed Nov. 25, 1985,now U.S. Pat. No. 4,677,182.

DESCRIPTION

1. Technical Field

This invention relates to adhesive compositions containing ioneneelastomers, sheet materials coated with such adhesive compositions, andto certain novel dibenzyl halide compounds useful in the preparation ofthe same.

2. Background Art

Polymers which include ions as an integral part of the polymeric chainare known as ionene polymers. Although a variety of structural types ofionene polymers are possible, by far the most common are polymericquaternary ammonium salts. The first examples of such ionene polymers,as reported by Gibbs and Marvel in J. Am. Chem. Soc. 57, 1137 (1935),were prepared by reaction of low molecular weight diamines with lowmolecular weight alkyl dibromides, producing a polymer as a crystallinesolid with a high ionic content which was insoluble in most organicsolvents and very soluble in water. Numerous examples of this type ofionene polymer have subsequently been described in the scientific andpatent literature, citing among other features their utility ascorrosion inhibitors, wet and dry strength additives, and antimicrobialagents.

It was observed that by substantially reducing the ionic content of theionene polymer by increasing the molecular weight of the oligomericfragments between quaternary ammonium links with a polymer having aT_(g) below room temperature, an elastomeric ionene polymer is produced.For example, Dolezal et al. (Rubber World, April 1968, page 46) studiedthe reaction of 4-6,000 MW polyisobutylene dibromides with variousorganic tertiary amines. The resulting ionenes were elastomeric but veryweak. Strength was developed in such elastomers only after beingcrosslinked with multifunctional amines. Dieterich et.al. have reviewedpolyester polyurethane ionenes [Angew. Chem. Int. Ed. Engl., 9, 40(1970)] and have investigated the effect of ionic content on elastomericproperties. Khojiya [Makrom. Chem. Rapid Comm. 2, 417 (1981)] disclosesan ionene prepared from a polytetramethylene oxide diamine of 1000molecular weight with 1,4-bis(chloromethyl)benzene as linking agent toproduce a weak elastomer with a tensile strength of 1370 kPa (200 psi)and elongation at break of 510%. Better physical properties werereported later (IUPAC Sixth Int. Symposium on Cationic Polymerizationand Related Processes. Abstract, Ghent, Belgium, Aug. 30-Sept. 2, 1983).Using 1,4-bis(chloromethyl)benzene again, but with a polytetramethyleneoxide diamine of 4,400 molecular weight, a film was made with 27,000 kPatensile strength (3900 psi) and 1000% elongation at break. However, suchelastomers exhibited high permanent set when extended to 500%elongation.

A series of patents by Buckler et al. describe the quaternization ofpendant tertiary amines with difunctional halides in a number ofstyrene-butadiene (SBR) gum rubbers (U.S. Pat. No. 3,969,330; U.S. Pat.No. 4,070,340), and of pendant halides in a halobutyl gum withdifunctional amines (U.S. Pat. No. 3,898,253), as a means of providingimproved green strength in the manufacture of tires and inner tubes.Although these elastomers are not true ionenes in the ordinary sense ofthe definition, the authors discovered that such crosslinks behaved asif they were labile. Under the action of mechanical shearing and heat,the Mooney viscosity of the cured elastomers was significantly reducedand the rubbers became readily millable. Furthermore, upon standing, theelastomeric properties were completely recovered and this was attributedto the reversibility of the quaternary ammonium links (Elastomerics,December 1977, page 32). These results are also consistent with another,perhaps more likely explanation; namely, that milling of the curedrubber causes rupture of hydrocarbon bonds which reduces the Mooneyviscosity but at the same time leaves the quaternary ammonium bondsintact. These ions would then be left as pendant groups along thepolymer chains. Upon standing, these ions aggregate into clusters whichact as physical crosslinks to re-establish green strength. Indeed, theauthors have demonstrated that such reversible elastomeric propertiescan be developed without chemical crosslinking in a halobutyl rubber bysimply quaternizing pendant alkyl bromides with monomeric tertiaryamines (U.S Pat. No. 4,256,857).

U.S. Pat. No. 3,904,580 appears to be the only disclosure of thepreparation of an elastomer which undergoes reversible quaternization.This patent describes a styrene butadiene copolymer with pendant aminescured with 1,4-bis(chloromethyl)benzene linking agent to provide acrosslinked quaternary ammonium elastomer which is capable of reversalof the quaternization when heated to 175° C. This linking agent is,however, slow to react with the pendant amines. This slowness ofreactivity is a common major disadvantage in most ionene elastomerpreparations. Most of the other reported preparations of true ioneneelastomers often require days of heating under reflux to achieveadequate degrees of polyquaternization.

SUMMARY OF THE INVENTION

The present invention provides novel ionene polymers and a method ofmaking the same. The ionene polymers of the invention have repeatingunits represented by formula I, as follows: ##STR1## wherein R is alower alkyl group of 1 to 4 carbon atoms (preferably a methyl group);

R' is a lower alkyl group of 1 to 4 carbon atoms (preferably a methylgroup) wherein R' may be the same as or different from R, and R' and Rmay be joined together with or without an additional hetero atom to forma heterocyclic ring, e.g., pyrrolidine, piperidine, or morpholine;

X is a halogen selected from the group consisting of Cl, Br, and I;

X' is a halogen selected from the group consisting of Cl, Br, and I andcan be the same as or different from X;

B is a divalent polymeric moiety having a molecular weight of about1,000 to about 50,000;

B' is a divalent polymeric moiety having a molecular weight of about1,000 to about 50,000 and may be the same as or different from B but, ifB and B' are different, at least one of B or B' has a T_(g) of less than20° C.;

AR is a phenylene or substituted phenylene radical;

Y is a divalent electron-donating substituent such as oxygen, nitrogenor sulfur; and

W is a divalent radical selected from the group consisting of (1) C₂₋₁₂alkylene selected from the group consisting of saturated C₂₋₁₂ alkyleneC₂₋₁₂ alkylene with one double bond, C₂₋₁₂ alkylene more than one doublebond, and C₂₋₁₂ alkylene with a triple bond, (2)--(CH₂ CH₂ O)₂ -CH₂ CH₂-- when Y is oxygen or sulfur, and (3) carbonyl, terephthaloyl, oradipoyl when Y is nitrogen.

More specifically, the method involves reacting one or more polymericdiamine represented by formula II and/or formula III, and one or moredibenzyl halide represented by formula IV and/or formula V, as follows:##STR2##

    X--CH.sub.2 --AR--Y--W--Y--AR--CH.sub.2 --X                IV

    X'--CH.sub.2 --AR--Y--W--Y--AR--CH.sub.2 --X'              V

The elastomers of the invention depolymerize rapidly, if desired, uponheating to relatively low temperatures, e.g., 145° C. to 200° C., togive the starting diamine and dibenzyl halide as gums or syrups whichmay be extruded to provide coatings or hot-melt adhesive compositions,or molded to provide elastomeric articles on cooling. The temperature atwhich the depolymerization occurs will vary depending upon theparticular halogen present in the elastomer. Elastomers wherein Xrepresents a Cl atom will depolymerize at lower temperatures, e.g., 145°C.-160° C., than where X represents Br or I.

The gums and syrups repolymerize on standing at or near ambienttemperature to provide an ionene which has substantially the samephysical characteristics and properties as that before depolymerization.

The invention also claims novel dibenzyl halides wherein W is furtherdefined as being C₇₋₁₂ alkylene.

DETAILED DESCRIPTION

In the preparation of ionene elastomers from the reaction of polymericdiamines with dihalides, the rate of polyquaternization as well as theultimate molecular weight achieved are determined by a number offactors. The molar concentration of reactive chain ends, the polarity ofthe medium, the inherent nucleophilicity of the diamine, and thereactivity of the dihalide all play a role. As the molecular weight ofstarting diamine oligomer is increased to obtain desired elastomericproperties, and then as the reaction proceeds, the concentration ofreactive chain ends necessarily diminishes, greatly reducing the overallrate and ultimate degree of polymerization. It may be necessary tocompensate for this effect by increasing the reactivity of the system.It is therefore preferred to employ diamines wherein R and R' representmethyl groups, particularly if B and B' are of high molecular weight, toobtain reasonably fast reaction rates.

The segment B or B' of diamine II and/or III can be any polymer having aT_(g) below room temperature. Suitable diamines are α,ω-bis(dimethylamino)polytetramethylene oxide, α, ω-bis(dimethylamino)polyisobutylene, α, ω-bis(dimethylamino) polyisoprene, α,ω-bis(dimethylamino) polypropylene oxide, and the like, preferably ofmolecular weight from about 1,000 to about 50,000. The most preferreddiamine is α, ω-bis(dimethylamino) polytetramethylene oxide, and optimumpolymerization rates are obtained for diamine of from about 5,000 toabout 25,000 molecular weight. Combinations of one or more differentdiamines may be employed to prepare novel ionene block copolymerelastomers. Minor amounts of polymeric diamines having a crystalline orhigh T_(g) (T_(g) above room temperature) B or B' group may also beused. Examples of such diamines include polymeric diamines α,ω-bis(dimethylamino) polymethylmethacrylate, α, ω-bis(dimethylamino)polystyrene, α, ω-bis(dimethylamino) polyethylene oxide, and the like,preferably in the 1,000-10,000 molecular weight range,

For the preparation of ionene elastomer according to the invention,diamine is treated with a stoichiometric amount of reactive dihalideeither in bulk or preferably in a solvent at a temperature of from about25° C. to about 125° C. Preferred solvents are polar and aprotic such asdimethylformamide, acetone, and ethyl acetate, with methyl ethyl ketoneand tetrahydrofuran being most preferred. The reaction is stirred,preferably under reflux, until the viscosity rises sufficiently, e.g.,to stop the magnetic stirrer, usually in from several minutes to as longas 24 hours depending on the structure of the dihalide employed.

In the case of the dihalide linking agents, a number of structuralvariations are possible which greatly increase the rate and degree ofpolymerization and enable the preparation of ionene elastomers withoutstanding properties. Preferred dibenzyl halides are those of FormulaIV and V which are substituted in the para position withelectron-donating substituents Y. This has been found to enhance thereactivity of the leaving group, X (and/or X'), and therebysignificantly increase the rate and degree of polymerization. Theactivated benzyl groups are joined by a link W of at least two andpreferably four or more carbon atoms. Such compounds include1,4-bis(p-bromomethylphenoxy) butane,N,N'-dimethyl-N,N'-bis(p-chloromethylphenyl)urea,1,4-bis(2-methoxy-5-chloromethylphenoxy) butane,1,6-bis(p-chloromethylphenylthio) hexane, diethyleneglycol-bis(p-bromomethylphenyl) ether,N,N'-dimethyl-N,N'-bis(p-chloromethylphenyl) adipamide, and1,4-bis(p-iodomethylphenoxy) butane.

Useful dibenzyl halides wherein W is C₂₋₆ alkylene are disclosed in U.S.Pat. No. 3,639,303. Dibenzyl halides wherein W is C₇₋₁₂ alkylene arenovel and a part of this invention.

Of course, the substituent which exerts the greatest effect on the rateand degree of polymerization is the halide, X (and/or X'). In agreementwith the well known order of reactivity of halogens toward displacement,in which I>Br>Cl, an elastomer with the highest molecular weight in theshortest reaction time was obtained using a substituted dibenzyl iodide.Nevertheless, for most ionene elastomer preparations, Br is sufficientlyreactive and is generally preferred as a leaving group, since thedibenzyl bromides are more easily prepared and are much more stable thandibenzyl iodides.

Although dibenzyl chlorides were significantly slower to react withpolymeric diamines than dibromides, surprisingly it was found thatmixtures of chlorides with small amounts of bromides gave polymerizationrates almost as fast as those of pure bromides.

The ionene elastomers of formula I are thermoplastic; when heated to aspecific minimum temperature, which is determined by the substituentschosen for X, X' and Y, the quaternization reverses to regenerate amineand benzyl halide, resulting in depolymerization to lower molecularweight gums or syrups which can be fabricated. The effect of theelectron-donating substituents, Y, in this reverse reaction is again oneof facilitation, resulting in dequaternization occurring at lowertemperatures than with unsubstituted analogs. The halide moiety, X(and/or X'), in this case is acting as a nucleophile, and the ease ofdequaternization parallels the relative reactivity of halidenucleophiles, with the chloride ionenes exhibiting lowerdepolymerization temperatures than bromides.

Just as it was found that the combination of dibenzyl bromide withchloride gave the fast rates of polymerization characteristic of purebromides, the same mixtures gave the low depolymerization temperaturescharacteristic of pure chlorides. Thus by utilizing mixtures of dibenzylhalides, it is possible to optimize the favorable characteristics ofboth bromides and chlorides, and to prepare ionene elastomers of highmolecular weight which depolymerize at reasonably low temperatures toavoid decomposition.

In choosing a polymeric diamine and reactive dibenzyl halide to preparea novel ionene elastomer, the preferred reactants are determined by theproperties required in the intended application. Since this is a type ofstep growth polymerization, an important factor in achieving maximumultimate molecular weight of any ionene is that whatever diamine ischosen have a functionality as close to 2.0 as possible. It is for thisreason that α, ω-bis(dimethylamino)polytetramethylene oxide has beenfound particularly attractive as a reactant, since it is readilyprepared in any desired molecular weight with excellent difunctionalityby the method of Smith and Hubin (U.S. Pat. No. 3,824,219).

In the case of the dibenzyl halides, the particular application againdictates the choice. For example, if an ionene elastomer is requiredthat has high heat stability, then a benzyl bromide or iodide such as1,4-bis(p-bromo (or iodo)methylphenoxy) butane is preferred. If it isdesired that the ionene depolymerize and flow upon heating, then eithera chlorobenzyl or a mixture of chloro and bromo benzyl halides could beemployed such as preferably1,4-bis(2-methoxy-5-chloromethylphenoxy)butane alone or in combinationwith 1,4-bis(4-bromomethylphenoxy)butane.

The elastomers of the present invention provide suitable base materialsfor adhesive compositions, particularly pressure sensitive adhesivecompositions. Pressure sensitive adhesive compositions may be preparedby blending the elastomers of the present invention with a suitabletackifier resin. Illustrative tackifier resins include alpha-pinenephenol tackifying resin and rosin ester tackifying resin such as thatavailable under the trade designation "Foral" 85. Preferably, the weightratio of tackifier resin to elastomer is in the range of about 50:100 to150:100.

Such adhesive compositions may include other conventional additivesnormally included in adhesive compositions and pressure sensitiveadhesive compositions. Such normal additives include stabilizers,fillers, ultraviolet light stabilizers and the like. The pressuresensitive adhesive compositions may be coated onto suitable backingmaterials to form adhesive coated sheet materials to provide tapes,labels, and the like. Suitable backing materials are formed of paper,plastic film such as polyester film (e.g., polyethylene terephthalate),metal foils, and the like.

This invention will be further demonstrated in the following examples,which will serve to illustrate not only the preparation of novel ioneneelastomers, but also the synthesis of novel dihalide and polymericdiamine starting materials. The details of the depolymerization of theseionenes will be described, as well as some of the outstanding propertiesof a number of the elastomers available by the practice of thisinvention. Finally, the formulation of an ionene elastomer into apressure sensitive adhesive composition will be presented.

EXAMPLE 1 Illustrating the preparation of alpha,omega-bis(dimethylamino)polytetramethylene oxide

A flame-dried 500 ml, 3-necked, round-bottomed flask equipped withmechanical stirrer, reflux condenser, N₂ inlet, and thermometer wascharged with 35 grams methylene chloride and 50 grams tetrahydrofuran(THF) previously dried over 3A molecular sieves. The solution was cooledto 0°-5° C. under dry N₂ with an ice-water bath. Trifluoromethanesulfonic anhydride (4.0 g) was added rapidly via syringe, and themixture was stirred with cooling for 15 minutes. Additional THF (90 g)was added dropwise over a 15-20 minute period at such a rate that thetemperature did not rise above 5° C. After addition was completed, thereaction was stirred for an additional 90 minutes at 0°-5° C.

The polymerization was terminated by pouring the viscous syrup into arapidly stirred solution of 12 g anhydrous dimethylamine condensed in 50ml of dry THF. After stirring at room temperature for 15 minutes, themixture was transferred to a 500 ml, one-necked, round-bottomed flaskwith 150 ml toluene, and the CH₂ Cl₂ and unreacted THF were stripped ona rotary evaporator. The residue was diluted with more toluene to avolume of 400 ml, treated with 50 ml of 25% aqueous NaOH, and stirredand heated at reflux for 10 minutes. The still warm mixture wastransferred to a separatory funnel, the lower aqueous layer discarded,and the organic phase dried over MgSO₄ and filtered through a Buchnerfunnel with a filter aid layer of diatomaceous earth available under thetrade designation "Super Cel". The clear, colorless solution wasconcentrated to dryness on a rotary evaporator to givebis(dimethylamino)polytetramethylene oxide as a light-yellow viscoussyrup in 60-65% yield. The polymer was dissolved in dry THF and storedas a 50% by weight solution. The molecular weight of the poly THFdiamine is calculated from the titration of a THF-isopropyl alcoholsolution with 0.1 N HCl to a bromphenol blue end point, and in thisexample was found to be 10,000. Higher molecular weight diamines areobtained by increasing the ratio of tetrahydrofuran to anhydrideinitiator, and conversely, lower ratios will give lower molecular weightoligomers. In this way, a series of poly THF diamines was prepared,ranging from 3,000 up to 27,500 MW.

EXAMPLE 2 Illustrating the preparation of alpha,omega-bis(dimethylamino) polymethyl methacrylate

An initiator/catalyst solution was prepared from 1.67 g (0.0068 moles)dimethylketene 3-dimethylaminopropyl trimethylsilyl acetal and 0.20 mlof a 0.1 M solution in acetonitrile of tris (dimethylamino) sulfoniumbifluoride (TASHF₂) in 60 ml THF (freshly distilled from potassiumketyl).

Twenty ml of this solution was charged to a 250 ml, 3-necked,round-bottomed flask fitted with thermometer, argon inlet, rubberseptum, and magnetic stirrer, followed by 38 ml of methyl methacrylate(previously purified by passage through a column of neutral aluminaunder argon) added dropwise via syringe. The addition was completed in20 minutes, and an exotherm to 60° C. was observed. Addition of another0.1 ml of TASHF₂ solution resulted in a highly exothermic reaction and afurther rise in temperature to 75° C.

Twenty ml of distilled THF was added and the solution cooled to 25° C.After an hour, addition of another 0.1 ml TASHF₂ solution gave only aslight exotherm. In another hour, after a final 0.1 ml TASHF₂ solutiongave no exotherm, the solution was cooled to 2° C. in an ice bath and16.35 ml of a 0.208 M THF solution of p-xylylene dibromide was addedover 20 minutes, followed by 9.02 ml of a 0.754 M acetonitrile solutionof tris(dimethylamino) sulfonium difluoro trimethyl silicate. Afterstirring for 11/2 hour, the mixture was warmed to 25° C., diluted with20 ml methanol, and heated under reflux for one hour. The solvent wasevaporated and the residue dissolved in acetone. The polymer solutionwas added to water and the precipitate collected by filtration and airdried. After drying in a vacuum oven at 75° C. overnight, there wasobtained 37.1 g of polymethylmethacrylate diamine as a white powder.

Theoretical yield=37.2 g (99.7%)

Gel permeation chromatography gave the following data: M_(n) =4,580M_(w) =10,795 D=2.36

Theoretical MW was 11,000; titrated MW (bromphenol blue end point) was16,090.

This example is based on a synthetic method described in U.S. Pat. No.4,414,372.

EXAMPLE 3 Illustrating the preparation of alpha,omega-bis(dimethylamino)polyethylene oxide from a commercially availablepolymer

A 500 ml, three-necked flask was flame dried and fitted with amechanical stirrer and nitrogen sweep. Eighty grams (0.1 mole) hydroxyterminated polyethyleneoxide (8000 MW) available under the tradedesignation "Dow" E-8000, was added to the flask along with 250 gtoluene. The resin was dissolved by heating with stirring, and thesolution was then cooled to room temperature. Phosgene was bubbledthrough the polymer solution until no free hydroxy was observed byinfrared spectroscopy (about 10 minutes). The reaction mixture wastransferred to a one liter, 1-necked flask, and excess toluene andphosgene were removed on a rotary evaporator. The solid residue, apolymeric bis-chloroformate, was redissolved in 150 ml THF. A one liter,three-necked flask, again equipped with mechanical stirring and anitrogen sweep, was charged with 2.3 g (10% excess)3-dimethylamino-1-propanol, 2.6 g (10% excess) triethylamine, and 100 mlTHF. The solution of the polymeric bis-chloroformate was then slowlyadded to the flask at room temperature with stirring.

After 60 minutes, insoluble salts were removed by filtration throughfilter aid, and the resulting solution was stripped of solvent on arotary evaporator. The residue was redissolved in chloroform and washedtwice with 10% aqueous sodium sulfate solution. The chloroform layer wasdried over MgSO₄, filtered, and evaporated to dryness on a rotaryevaporator, to give polyethylene oxide bisdimethylamine as acrumbly-white solid in 80% yield. The titrated molecular weight was8,375.

EXAMPLE 4 Illustrating the preparation of the intermediate1,4-bis(p-hydroxymethylphenoxy)butane

A 1000 ml, 3-necked, round-bottomed flask fitted with thermometer,reflux condenser, nitrogen inlet, and mechanical stirrer was chargedwith 122.1 g p-hydroxybenzaldehyde (1.0 mole), 108 g. 1,4-dibromobutane(0.5 mole), 212 g powdered anhydrous Na₂ CO₃ (2.0 moles), and 300 ml drydimethylformamide. The mixture was stirred and heated to 130° C. for 5hours. The reaction was cooled to room temperature, poured into oneliter of ice water, and the brown precipitate filtered and washed wellwith water. The wet cake was then dissolved in 300 ml CHCl₃ and washedtwo times with 200 ml H₂ O and once with 200 ml 10% HCl. The organiclayer was dried (MgSO₄), filtered, and evaporated to dryness on a rotaryevaporator to give a solid mass. The product was slurried in ether,filtered, washed with ether, and air dried, to provide1,4-bis(p-carboxaldehydo)phenoxybutane as a light-orange crystallinesolid. TLC (silica gel/EtOAc) showed only one spot. The yield was 97 g(65%).

Eighty-seven grams of the above bis-aldehyde (0.29 mole) was slurried in250 ml of 95% EtOH in a 500 ml, three-necked, round-bottomed flask, 11.0g NaBH₄ (0.29 mole) were added, and the mixture was heated under refluxwith magnetic stirring. The course of the reduction was followed byperiodically withdrawing a sample by pipette, precipitating the productin water, and observing the disappearance of the carbonyl peak in the IRspectrum. After six hours, the aldehyde was completely reduced, and thereaction was poured without cooling into one liter of cold water. Thewhite solid was filtered, washed with water, and air dried. The cake wastriturated in 200 ml methanol, cooled in ice and filtered, washed withcold methanol, and air dried. The white, crystalline diol had an IR andNMR spectrum in agreement, with the desired structure and was pure byTLC. The yield was 80 g (91%).

Using the general procedure of Example 4, a number of additionalintermediate dibenzyl alcohols were prepared.

EXAMPLE 5 Illustrating the preparation of the intermediateN,N'-dimethyl-N,N'-di(p-hydroxymethylphenyl) urea

A 500 ml, three-necked, round-bottomed flask was charged with 66.1 gethyl-p-aminobenzoate (0.4 mole), 44.6 g triethylamine (0.44 mole), and200 ml dry THF. The solution was stirred and cooled to 0° C., and asolution of 22 g phosgene (0.21 mole) in 100 ml dry THF was addeddropwise over a half-hour period. A heavy precipitate of triethylaminehydrochloride began to form immediately. The mixture was stirred for onehour after the addition was completed and then poured into one liter of10% HCl to give a pale-yellow solid. The crude product was filtered,washed with water, and air-dried. The damp cake was slurried in MeOH,filtered, washed with methanol, and air dried, to give 56.8 g (80%) ofdiphenyl urea diester as a pure-white crystalline solid. The yield was36.4 g (59%).

The ester was hydrolyzed by dissolving in 200 ml 95% ethanol, adding 25g of 50% NaOH, and heating under reflux for 2 hours. After pouring into500 ml water, the clear solution was acidified with 10% HCl. Theflocculent white precipitate was filtered, washed with water, and thedamp cake triturated with 2-butanone. After filtration, washing withether, and air drying, there was obtained 26.8 g of diacid (86% yield).

This material was slurried in 200 ml ethylene dichloride, and 25 gthionyl chloride was added and the mixture heated at reflux under N₂.The solid dissolved slowly while evolving SO₂ and HCl gas, until aclear-yellow solution was obtained. After two hours, HCl evolution hadceased, and the reaction was evaporated to dryness on a rotaryevaporator. The resulting yellow gummy solid was slurried in hexane,filtered, and washed with hexane, to give 30.0 g (100% yield) of diacidchloride urea as a pale-yellow crystalline solid.

For reduction to diol, this product was dissolved in THF and addeddropwise with stirring to a slurry of 11.2 g NaBH₄ (0.29 mole) in 100 mlisopropanol at 0°-5° C. After addition was completed, the solution wasstirred for one hour at room temperature. Water (300 ml) was addedslowly to the reaction, and the precipitate was extracted into ethylacetate. The ethyl acetate solution was washed with three 100 mlportions of water, dried (MgSO₄), and stripped, to give the productN,N'-dimethyl-N,N'-di(p-hydroxymethylphenyl) urea as a light-yellow oilwhich would not crystallize. TLC (silica gel/EtOAc) showed the productto be quite pure.

A similar procedure was used to prepareN,N'-dimethyl-N,N'-di(p-hydroxymethylphenyl) terephthalamide as well asadipamide, starting from ethyl p-aminobenzoate and terephthaloylchloride and adipoyl chloride, respectively. In these cases, theproducts were obtained as white crystalline solids after triturationwith toluene and ether.

EXAMPLE 6 Illustration of the preparation of1,4-bis(p-bromomethylphenoxy) butane

In a one liter, three-necked, round-bottomed flask a slurry of 75 g1,4-bis(p-hydroxymethylphenoxy) butane, 250 ml chloroform, and 250 ml48% hydrobromic acid was stirred mechanically and heated to 45° C. Asthe reaction proceeded, the diol slowly dissolved in the CHCl₃ until,after three hours, the organic layer was completely clear. In anotherhour, the product dibromide began to precipitate. After three morehours, the slurry was cooled to room temperature, diluted with coldwater, and filtered. The crude product was washed with water andsuctioned to near-dryness with air. The light-orange solid wasrecrystallized twice from 2-butanone, to give off-white needles ofdibenzyl bromide which were pure by TLC. The yield was 75 g (70%), m.p.138°-140° C.

EXAMPLE 7 Illustration of the preparation of N,N'-dimethyl-N,N'-bis(p-chloromethylphenyl) urea

A solution of 10 g N,N'-dimethyl-N,N'-bis(p-hydroxymethylphenyl) urea in250 ml CHCl₃ was stirred vigorously for two hours with 250 ml conc. HCl.The layers were separated, and the organic phase was washed with diluteHCl, dried, and stripped to give a yellow oil. Trituration with hexanecaused the product to crystallize. Filtration, washing with hexane, andair drying gave 3.5 g of a fluffy-white crystalline solid which was pureby TLC, m.p. 72°-73° C.

EXAMPLE 8 Illustration of the preparation of1,4-bis(2-methoxy-4-chloromethylphenoxy) butane

A solution of 22 g 1,4-bis(2-methoxy-4-hydroxymethylphenoxy) butane in200 ml warm CHCl₃ was added dropwise to a solution of 60 ml SOCl₂ in 100ml CHCl₃. After the addition was completed, the chloroform was boiledoff while replacing with heptane. When the temperature reached theboiling point of heptane (97° C.), the solution was decanted from asmall amount of yellow oil and allowed to cool. Decantation from oilyimpurities was continued until the white crystalline product began toform. The solution was cooled, and, after crystallization was completed,the product was filtered, washed with hexane, and air dried. One morerecrystallization from heptane gave a pure-white crystalline productwhich was one spot on TLC. The yield was 23 grams, m.p. 116°-118° C.

EXAMPLES 9-18

By the methods of Examples 6, 7, or 8, the following dibenzyl halideswere prepared from the intermediate dibenzyl alcohols:

    ______________________________________                                        Example                         m.p.                                          Number Compound                 (°C.)                                  ______________________________________                                         9     1,10-bis(p-bromomethylphenoxy) decane                                                                  94-96                                         10     1,4-bis(2-methoxy-5-bromomethyl-                                                                       155-157                                              phenoxy)butane                                                         11     diethylene glycol-bis( -p-bromomethyl-                                                                 91-93                                                phenyl)ether                                                           12     N,N'--dimethyl-N,N'--bis(p-bromomethyl-                                                                75-77                                                phenyl)urea                                                            13     1,4-bis(2-methoxy-4-bromomethyl-                                                                       143-145                                              phenoxy)butane                                                         14     1,10-bis(p-chloromethylphenoxy)decane                                                                  82-83                                         15     1,4-bis(2-methoxy-5-chloromethyl-                                                                      128-131                                              phenoxy)butane                                                         16     diethylene glycol-bis( -p-chloromethyl-                                                                71-73                                                phenyl)ether                                                           17     N,N'--dimethyl-N,N'--bis(p-chloromethyl-                                                               213-217                                              phenyl)-terephthalamide                                                18     N,N'--dimethyl-N,N'--bis( -p-chloromethyl-                                                             75-76                                                phenyl)-adipamide                                                      ______________________________________                                    

EXAMPLE 19 Illustration of the preparation of1,4-bis(p-iodomethylphenoxy)-butane

A solution of 3.9 g of 1,4-bis (p-bromomethylphenoxy) butane in 50 ml2-butanone was added to a solution of 9.7 g NaI in 100 ml 2-butanone.After an initial exothermic reaction, a golden-yellow precipitateformed. The product was filtered, washed with water, and air dried.Recrystallization from xylene gave the diiodide as a golden-yellowcrystalline solid. The yield was 2.0 g.

EXAMPLE 20 Illustration of the effect of substituents on the rate ofpolymerization and on the ultimate molecular weight of ionene elastomers

The standard procedure for the preparation of ionene elastomers is todissolve 10.0 g of the diamine in 50 ml of dry THF, add a stoichiometricequivalent of dibenzyl halide, and heat the solution under reflux underN₂ with magnetic stirring until the solution becomes too viscous tostir. An antioxidant, available under the trade designation "Irganox"1010, is dissolved (0.1 g, 1% by weight) in the syrup, which is castinto a glass petri dish and the solvent allowed to evaporate for 4-5hours. Final drying is accomplished in a 65° C. forced air oven for 16hours to provide clear, colorless elastomer films.

The results of a number of runs of poly THF diamines with variousdibenzyl halides are presented in Table 1.

                                      TABLE 1                                     __________________________________________________________________________       Molec.                                                                        Weight                          I.V..sup.(1)                               Run                                                                              Diamine                                                                            Dihalide            Polym. Time                                                                          (dl/0.4 g)                                 __________________________________________________________________________     1*                                                                              8,000                                                                               ##STR3##           16 hr  1.4                                         2*                                                                              8,000                                                                               ##STR4##           18 hr  1.6                                        3  8,000                                                                               ##STR5##           8  hr  2.4                                        4  8,000                                                                               ##STR6##           8  hr  3.1                                        5  10,000                                                                              ##STR7##           6  hr  1.8                                        6  10,000                                                                              ##STR8##           5  hr  2.0                                         7*                                                                              8,000                                                                               ##STR9##           20 min 2.8                                        8  8,000                                                                               ##STR10##          10 min 4.7                                        9  10,000                                                                              ##STR11##          15 min 4.2                                        10 8,000                                                                               ##STR12##          1  hr  4.6                                                 ##STR13##                                                            11 8,000                                                                               ##STR14##          30 sec 5.1                                        12 14,000                                                                              ##STR15##          72 hr  2.6                                        13 14,000                                                                              ##STR16##          30 min 3.8                                        14 14,000                                                                              ##STR17##          31/2                                                                             hr  3.3                                                 ##STR18##                                                            15 27,500                                                                              ##STR19##          1  hr  3.0                                        __________________________________________________________________________     *Control examples                                                             .sup.(1) CHCl.sub.3 solution, measured at 25° C. in a CannonFenske     #50 viscometer.                                                          

In considering the results listed in Table 1, it is apparent thatelectron-donating substituents on the dibenzyl halide greatly increasethe rate of reaction compared to a reactive dialkyl halide or anunsubstituted dibenzyl chloride (Runs 3-6 with Runs 1 and 2). Thegreatest increase in rate is effected by changing the leaving group(Runs 4, 8, and 11). Even though the dibenzyl bromides had similar ratesof polymerization, the presence of electron-donating substituents led tosubstantially higher molecular weights (Run 7 with Runs 8 and 9).Combinations of bromides with chlorides gave rate increases comparableto pure bromides (Runs 3 and 8 with Run 10; and Runs 12 and 13 with Run14).

EXAMPLE 21 Illustrating the excellent elastomeric properties exhibitedby the ionenes prepared according to Example 20

Table 2 lists the tensile properties of a number of representative polyTHF ionene elastomers and several ionene block copolymer elastomers asmeasured on a tensile testing device available under the tradedesignation "Instron" Model 1125 at a crosshead speed of 500 mm/min witha 500 kg load according to ASTM D412.

                                      TABLE 2                                     __________________________________________________________________________    pTHF           Dihalide      100% 300%                                        Diamine        Example                                                                            Tensile                                                                           Elonga-                                                                            Modulus                                                                            Modulus                                     MW (%) Copolymer (%)                                                                         (X)  (kPa)                                                                             tion (%)                                                                           (kPa)                                                                              (kPa)                                       __________________________________________________________________________    1 7350         8 (Cl)                                                                             35,060                                                                            1,100                                                                              1520 1900                                        2 8500         8 (Cl)                                                                             29,370                                                                            1,000                                                                              1590 2210                                        3 10,000       7 (Cl)                                                                             38,540                                                                            760  1210 1650                                        4 10,000       6 (Br)                                                                             33,920                                                                            650  1590 2070                                        5 10,000 (80)                                                                        Poly EO (20)                                                                          6 (Br)                                                                             47,570                                                                            590  --   8140                                        6 10,000 (80)                                                                        Poly MMA (20)                                                                         6 (Br)                                                                             42,260                                                                            610  2830 9170                                        __________________________________________________________________________

EXAMPLE 22 Illustrating the effect of substituents on the "melting"(depolymerization) points of poly THF ionene elastomers

In this study, a number of elastomer film samples were heated in atesting device available under the trade designation "Thermo MechanicalAnalyzer" at a rate of 10°/min, and the "melting" (depolymerization)point was taken as the temperature at the midpoint measured from theonset of the softening to complete penetration of the probe. Results fora series of poly THF ionene elastomers obtained from various dibenzylhalides are shown in Table 3.

                  TABLE 3                                                         ______________________________________                                             pTHF                                                                          Diamine                          M.P.                                    Run  MW       Dihalide (Example)      (°C.)                            ______________________________________                                        1    8,000                                                                                   ##STR20##              144°                                           +                                                                              ##STR21##                                                      2    8,000                                                                                   ##STR22##              146°                             3    10,000                                                                                  ##STR23##              147°                             4    14,000                                                                                  ##STR24##              149°                             5    8,000                                                                                   ##STR25##              157°                             6    8,000                                                                                   ##STR26##              157°                             7    14,000                                                                                  ##STR27##              160°                             8    8,000                                                                                   ##STR28##              179°                             ______________________________________                                    

From these results it can be concluded that the "melting" points ofthese elastomers are dependent on the substituents of the dibenzylhalides and not on the molecular weight of the amine fragment (Runs 2and 4 with Runs 6 and 7). Bromides are higher "melting" than chlorides(Runs 6-8 with Runs 1-5). Electron-donating substituents promote alowering of the "melting" point compared to unactivated dibenzyl halides(Runs 2-4 with Run 5, and Runs 6 and 7 with Run 8). The "melting" pointof a mixture of dibenzyl chloride and bromide is approximately the sameas that of a pure chloride (Run 1 with Runs 2-4).

EXAMPLE 23 Illustrating that the "melting" of ionene elastomers of thisinvention is a depolymerization, and also illustrating how the meltsrepolymerize in time

In this study, samples of solid elastomer films were heated (in vesselsin an oil bath heated to the specified temperature and preferably underN₂) for the minimum amount of time required for the film to become fluid(usually 10-15 minutes). A sample of the gum or syrup was immediatelydissolved in CHCl₃ for determination of the inherent viscosity of themelt. The remainder was placed in a 65° C. oven and periodically sampledto determine changes in viscosity with time, if any. Results are shownin Table 4.

                                      TABLE 4                                     __________________________________________________________________________    Melt Behavior of Ionene Elastomers                                                                     Inherent Viscosity                                                            (dl/0.4 g) in CHCl.sub.3                             __________________________________________________________________________    Ionene 1:                                                                      ##STR29##                                                                                  Original Elastomer                                                                       2.37                                                               Melt (145° C., 10 min)                                                            0.88                                                               2 hr (65° C.)                                                                     1.26                                                               18 hr (65° C.)                                                                    2.19                                                               42 hr (65° C.)                                                                    2.27                                                 Ionene 2:                                                                      ##STR30##                                                                                  Original Elastomer                                                                       1.95                                                               Melt (140° C., 15 min)                                                            1.17                                                               18 hr (65° C.)                                                                    1.69                                                 Ionene 3;                                                                      ##STR31##                                                                    Cl:Br = 3:1                                                                                 Original Elastomer                                                                       3.22                                                               Melt (145° C., 7 min)                                                             1.00                                                               18 hr (65° C.)                                                                    2.21                                                 __________________________________________________________________________

Even though the molten syrups resolidify to strong elastomers shortlyafter cooling to room temperature, it is seen from the I.V. data of theTable that the actual molecular weight is slow to build in the solidstate even with annealing at 65° C. However, in time the ionenes dorecover at least 70-95% of their initial molecular weight.

EXAMPLE 24 Illustrating the preparation of a pressure sensitive adhesivecomposition from an ionene elastomer and a tackifying resin

An ionene elastomer prepared fromα,ω-bis(dimethylamino)polytetramethylene oxide of 10,000 MW and1,4-bis(2-methoxy-5-chloromethylphenoxy) butane (IV=2.34) was blendedwith an α-pinenephenol tackifying resin. A 100 phr sample was preparedby dissolving 4.0 g of the elastomer and 4.0 g of tackifying resin in a32.0 g of CHCl₃ and a 120 phr sample consisted of 4.0 g elastomer and4.8 g tackifier resin in 35.2 g of CHCl₃. Each of these compositions wascast on polyester film, allowing the solvent to evaporate for 20 minutesat room temperature and then for 10 minutes in a 65° C. oven. Afteraging at 20° C. for 18 hours, conventional testing procedures wereemployed to determine peel adhesion to glass and shear adhesion at 20°C. and at 65° C. Results are reported below, along with detaileddescriptions of the test methods utilized.

    __________________________________________________________________________    Adhesive    Peel Adhesion Glass                                                                     Shear (20° C.)                                                                 Shear (65° C.)                           Thickness (mm)                                                                            (N/100 mm)                                                                              1 kg (min.)                                                                           1 kg (min.)                                     __________________________________________________________________________    100 phr                                                                           0.02    61        10,000+ 200                                             120 phr                                                                           0.02    74        10,000+ 100                                             __________________________________________________________________________

Almost identical results were obtained using a rosin ester tackifyingresin available under the trade designation "Foral" 85.

TEST METHODS

The test methods used to evaluate the psa-coated flexible sheetmaterials of the above example are industry standard tests. The standardtests are described in detail in various publications of the AmericanSociety for Testing and Materials (ASTM), Philadelphia, Pennsylvania andthe Pressure Sensitive Tape Council (PSTC), Glenview, Illinois.

Shear Strength (Reference: ASTM: D3654-78; PSTC-7)

The shear strength is a measure of the cohesiveness or internal strengthof an adhesive. It is based upon the amount of force required to pull anadhesive strip from a standard flat surface in a direction parallel tothe surface to which it has been affixed with a definite pressure. It ismeasured in terms of time (in minutes) required to pull a standard areaof adhesive-coated sheet material from a stainless steel test panelunder stress of a constant, standard load.

The tests were conducted on adhesive-coated strips applied to astainless steel panel such that a 12.5 mm by 12.5 mm portion of eachstrip was in firm contact with the panel with one end portion of thetape being free. The panel with coated strip attached was held in a racksuch that the panel forms an angle of 178° with the extended tape freeend which is then tensioned by application of a force of one kilogramapplied as a hanging weight from the free end of the coated strip. The2° less than 180° is used to negate any peel forces thus insuring thatonly the shear forces are measured in an attempt to more accuratelydetermine the holding power of the tape being tested. The time elapsedfor each tape example to separate from the test panel is recorded as theshear strength.

Peel Adhesion Reference: ASTM D3330-78 PSTC-1 (11/75)

Peel adhesion is the force required to remove a coated flexible sheetmaterial from a test panel measured at a specific angle and rate ofremoval. In the example, this force is expressed in Newtons per 100 mm(N/100 mm) width of coated sheet. The procedure followed is:

1. A 12.5 mm width of the coated sheet is applied to the horizontalsurface of a clean glass test plate with at least 12.7 lineal cm in firmcontact. A hard rubber roller is used to apply the strip.

2. The free end of the coated strip is doubled back nearly touchingitself so the angle of removal will be 180°. The free end is attached tothe adhesion tester scale.

3. The glass test plate is clamped in the jaws of a tensile testingmachine which is capable of moving the plate away from the scale at aconstant rate of 2.3 meters per minute.

4. The scale reading in Newtons is recorded as the tape is peeled fromthe glass surface. The data is reported as the average value of therange of numbers observed during the test.

We claim:
 1. A pressure sensitive adhesive composition comprising the ionene elastomer repeating units represented by the formula: ##STR32## Wherein: R is a lower alkyl group of 1 to 4 carbon atoms;R' is a lower alkyl group of 1 to 4 carbon atoms wherein R' may be the same as or different from R, and R' and R may be joined together with or without an additional hetero atom to form a heterocyclic ring; X is a halogen selected from the group consisting of Cl, Br, and I; X' is a halogen selected from the group consisting of Cl, Br, and I and can be the same as or different from X; B is a divalent polymeric moiety having a molecular weight of about 1,000 to about 50,000; B' is a divalent polymeric moiety having a molecular weight of about 1,000 to about 50,000 and may be the same as or different from B but, if B and B' are different, at least one of B or B' has a T_(g) of less than 20° C.; AR is a phenylene or substituted phenylene radical; Y is a divalent electron-donating sustituent; and W is a divalent radical selected from the group consisting of (1) a C₂₋₁₂ alkylene selected from the group consisting of saturated C₂₋₁₂ alkylene, C₂₋₁₂ alkylene with one double bond, C₂₋₁₂ alkylene with more than one double bond and C₂₋₁₂ alkylene with a triple bond, (2) --(CH₂ CH₂ O)₂ --CH₂ CH₂ --when Y is oxygen or sulfur and (3) carbonyl, terephthaloyl, or adipoyl when Y is nitrogen and sufficient compatible tackifier to endow the composition with a degree of adhesive tack to provide a pressure sensitive adhesive.
 2. The pressure sensitive adhesive composition of claim 1 wherein the weight ratio of tackifier to the ionene elastomer is in the range of about 50:100 to about 150:100. 